When she arrived back in her hometown of New York City after attending Bennington College, Helen Frankenthaler (1928–2011) was precociously talented, notoriously beautiful, and eager to take on the world. The year was 1950, and she spent the next decade pushing abstract painting into new territory, the beginning of a long career that was one of the twentieth century’s most distinguished in art.

The work that she did as a twentysomething—ahead of her time, and not appreciated until later—is now the subject of a new exhibition at New York’s Gagosian Gallery opening Friday, “Painted on 21st Street: Helen Frankenthaler from 1950 to 1959.” The 29 works on view include her breakthrough painting, Mountains and Sea (1952), in which she started staining part of the canvas, an early step in the transition from Abstract Expressionism to color field painting.

The Museum of Modern Art curator emeritus John Elderfield, known for his Matisse exhibitions, organized the show with Frankenthaler’s estate. He met the artist in 1976 and still recalls it vividly. “I had just opened my first MoMA show, of Fauvist painting,” Elderfield says. “Helen wrote me a note saying, ‘Great show! Keep going.’ And then a few days later she called me and said, ‘I was wondering, would you want to write a book about me?’ Those were the two sides of Helen, one gracious and generous, and the other determined.”

A native Upper East Sider who attended Dalton, Frankenthaler set up a studio on East Twenty-first Street and wasted no time in stirring up the art world. “She was bubbling with confidence,” Elderfield says. “She organized a show of Bennington artists, and to help get people to come, she promised there would be martinis.” Frankenthaler embarked on a five-year relationship with the most influential art critic of the era, Clement Greenberg, and set about painting highly abstracted landscapes and figures like The Juggler, a 1951 work in the Gagosian show.

From the beginning, her sense of color, composition and balance was spot-on, and she was prolific for the next 50 years. “I don’t like to over-worry a surface and make it look labored,” she told me in 2003, in her last major interview. “Whatever medium it is, I like it to look fresh.” Not that people noticed right away. “She exhibited a lot in the 1950s, but she hardly sold anything,” Elderfield says. “Even Mountains and Sea had no takers at $100.”

Elderfield urges audiences at the Gagosian show to consider Frankenthaler’s 1950s work on its own terms—it’s only the second exhibition ever in New York devoted to that decade in her oeuvre. “Her art makes a lot of work done today look very tidied up,” says Elderfield. “The paintings still seem very contemporary.” And even though she charted a turning point in the history of art, no knowledge of what came later is needed to savor these paintings. “She’s not a bridge,” as Elderfield puts it. “She’s a destination.”

“Painted on 21st Street: Helen Frankenthaler from 1950 to 1959” is on view through April 13 at the Gagosian Gallery, 522 West 21st Street; gagosian.com